Figure 4.

Schematic illustration of the effects of metal salt precursor on the morphology of
Co3O4 on CuO NWs. A CuO NW is dip-coated with a cobalt precursor solution containing the solvent and
cobalt salt and then annealed in the flame. (Left column) In the case of a volatile
precursor (e.g., Co(CH3COO)2·4H2O), the precursor evaporates into vapor and nucleation of the Co3O4 occurs in the gas phase, resulting in the formation of the NP-chain morphology. (Right
column) In the case of a non-volatile precursor (e.g., Co(NO3)2·6H2O), the precursor does not evaporate but stays in the solvent, where nucleation happens
in the liquid phase, resulting in the formation of the shell morphology.